Antenna horn



@w55 mmf-imm June 14, 1960 A. J. PRICKETT ANTENNA HORN Filed Deo. '7, 1954 3 Sheets-Sheet 1 y M K June 14, 1960 A. J. PRlcKE-TT ANTENNA HORN 3 Sheets-Sheet 2 Filed Deo. '7, 1954 June 14, 1960 A. J. PRICKETT ANTENNA HORN 3 Sheets-Sheet 3 Filed Dec. 7, 1954 n@ IWW l l l l l l l I l l I z L /N VE N T01? ATTO/@NIV United States Patent O ANTENNA HORN Alfred Prickett, Des Plaines, Ill., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Filed Dec. 7, 1954, Ser. No. 473,505

1 Claim. (Cl. 343-705) This invention relates to an antenna horn having a waveguide aperture therethrough for a high velocity radar controlled device.

An object of the invention is to provide an antenna horn having a streamlined contour and a waveguide aperture therethrough.

Another object of the invention is to provide an antenna horn formed by casting a preformed waveguide tube of precise dimensions in a streamlined antenna horn without distorting the tube.

A method and apparatus illustrating the production of the antenna horn may include a sectional mold having a mold cavity of a predetermined streamlined shape and having a pair of cylindrical supporting pins axially movable into the straight end portions of an accurately bent cylindrical metal waveguide tube with the ends of the pins in abutting relation for supporting the accurately precise walls of the tube against collapse or distortion land to position the tube in ya predetermined position in the mold cavity. With the tube supported in the mold, molten metal is forced into the mold cavity to mold a metal horn body with a predetermined streamlined contour around the tube, and the tube forms an uninterrupted accurate waveguide aperture through the horn of predetermined longitudinal and of uniform precise cross-sectional configuration.

Other objects and advantages of the invention will become apparent by reference to the following detailed description illustrating a preferred embodiment of the invention, in which Fig. 1 is a side elevational view of the antenna horn;

Figs. 2 and 3 are opposite end views of the antenna horn shown in Fig. 1;

Fig. 4 is a fragmentary vertical sectional view through a molding apparatus for molding the antenna horn;

Fig. 5 is an enlarged fragmentary sectional view through the molding dies of the molding apparatus taken along the line 5--5 of Fig. 4;

Fig. 6 is an oblique elevational view of a portion of the mounting dies looking in the direction of the arrows and the broken line 6-6 on Fig. 5; and

Fig. 7 is a fragmentary oblique longitudinal sectional view through the molding dies taken along the line 7-7 of Fig. 5.

Referring to the drawings, Figs. l, 2, and 3 show different views of an antenna horn 10 comprising a body 11 of metal molded around an accurately bent tube 12 which provides a precise waveguide aperture through the horn. The tube 12 is made from a cylindrical stainless steel tube which is bent intermediate its ends to provide two straight end portions 16 and 17 and a curved knee portion 18 and has a precise uniform circular crosssectional configuration throughout its length and smooth interior surfaces. The body 11 of the antenna horn is substantially triangular as viewed from the side (Fig. 1) and the opposite sides 19, 19 thereof slope toward the left (as viewed in Fig. 1) from the widest portion over the tube 12 to a sharp edge 20 and slope toward the right Patented June 14, 1960 from the widest portion to a sharp point 21. The antenna horn is adapted to be placed on a radar controlled device with the substantially flat face 22 thereof in engagement with the device and with a circular attaching ange 23 extending from the at face 22 engageable in a recess in the device. A cylindrical aligning sleeve 24 of the body 11 projects from the face of the flange 23 and around the portion 17 of the tube 12 and terminates short of the end thereof.

A molding apparatus 30 (Fig. 4) for molding the antenna horn 10 comprises a base or bed 31 on which are mounted a stationary platen 32 and a stationary head 33, which is formed integral with a cylinder 34 of a hydraulic actuator for reciprocating a ram 35. A movable platen 36 is mounted on the end of the ram and is guided for horizontal movement by a plurality of guide rods 37 secured to the stationary platen 32 and the head 33. A sectional mold is provided having a stationary die section 40 secured to the stationary platen 32 and a movable die section 41 secured to the ends of a plurality of supporting rods 42 which are fixed to the movable platen 36 for movement of the rods and the movable die section therewith. The stationary and movable die sections are provided with recesses 44-44 (Fig. 7) conforming to the side portions of the antenna horn, and a slidable die section 47 carried by the movable die section 41 has a lower recessed surface 48 conforming to a portion of the antenna horn for cooperation with the stationary and movable die sections 40 and 41 to form a die cavity 50 for molding the antenna horn therein about the waveguide tube 12.

The slidable die section 47, which is of substantially rectangular outline, ts in rectangular recesses 52 and 53 in the stationary and movable die sections and is slidably retained on the movable die section 41 by keys 54 for movement to and from a closed position shown in full lines in Fig. 7 and an open position shown in dotted lines therein. The slidable die section 47 is movable to and from open and closed positions in response to horizontal movement of the movable die section 41 to and from open and closed positions by a pair of inclined camming elements or angle pins 55 which are secured to the stationary die section 40 and cooperate with inclined cam surfaces 56 formed by the upper and lower surfaces of a pair of inclined apertures 57 in the slidable die section 47. Thus, in response to the movement of the movable die section 41 from its closed position shown in Fig. 4 to its open position shown in dotted lines in Fig. 7 the inclined cam rods 55 will raise the slidable die section 47 to its open position, and in response to the movement of the movable die section 41 from its open position to its closed position the cam rods 55 serve to move the slidable die section downwardly substantially to its closed position. An inclined shoulder 60 on the slidable die section 47 forms a cam surface which cooperates with the cam surface on a shoulder 61 formed on the stationary die section 40 for wedging the slidable die section 47 downwardly into tight engagement with the bottom of the recesses 52 and 53 of the stationary and the movable die sections 40 and 41, respectively, during the final portion of the movement of the movable die section 41 to its closed position.

The waveguide tube 12 is supported in a predetermined position in the mold cavity 50 by the pair of movable pins 63 and 64, the latter of which is secured to the slidable die section 41 for movement therewith. The projecting end of the core pin 64 is adapted to tit into the straight end portion 17 of the tube 12 and has a peripheral surface conforming to the interior of the straight portion of the tube 12 and a portion of the curved knee 18 thereof as shown in Fig. 5 and has a flat end face 65 adapted to abut against a similar fiat end face 66 of the pin 63. The pin 63, which is mounted for horizontal movement in a guide member `67, is adapted to fit into the straight end portion 16 of the tube 12 and has a peripheral surface conforming to the interior of the straight portion 16 and a portion of the curved knee 18 thereof for cooperating with the pin 64 to support the tube 12 against deformation or collapse during the molding of the body 11 therearound and to position the tube 12 in a predetermined location in the mold cavity 50. The core pin 63 is connected to a rack bar 68 supported for horizontal movement in a bracket 69 which is secured to the movable die section for movement therewith. The rack bar 68 meshes with a pinion 70 fixed to a shaft 71 which is rotatably supported in the bracket 68 and is connected to a handle 72, by means of which the rack bar may be reciprocated to advance and retract the pin 63.

A predetermined amount of molten metal is poured through a filling aperture 75 into the chamber 76 of a cylinder 77 in the stationary platen 32 and die 40, and a ram 78 is actutated to force the molten metal through a passageway 80 and a gate 81 in the movable die section 41 into the die cavity 50. The molten metal fills the die cavity 50 around the waveguide tube 12 and the excess metal iiows from the die cavity into a plurality of overflow pockets or recesses 82 in the movable die section 41. After the molten metal has hardened and the movable and slidable die sections 41 and 47 have been moved to their open positions, the molded antenna horn 10 and the excess metal adhering thereto are ejected from the movable die section by a plurality of pins 84 engageable with the overow portions of the metal casting. The ejecting pins 84 are secured to a plate 83 which is slidably supported for limited hor-izontal movement on a plurality of shouldered rods 90 fixed to theV movable die section 41. The ejecting plate 83 is connected to a piston rod 85 of a piston 86 which is reciprocable in a cylinder 87 carried by the movable platen 36 and is adapted to be actuated to advance the ejecting pins 84 and eject the molded antenna horn 10.

Molten metal is forced into the die cavity under a pressure of approximately 2500 pounds per square inch on the metal which gives a sound casting and in cooperation with the suporting pins 63 and 64 provides a uniform waveguide without deformation.

In the molding of the antenna horn and wtih the movable die section 41 and the slidable die section 47 in their open positions, the tube supporting pin 63 is moved to its inner or operative position as shown in Fig. and the straight end portion 16 of the tube 12 is telescoped thereover and positioned thereon -in a predetermined position in the die cavity 50 with the end of the tube 12 in engagement with the shoulder 86 of the supporting pin 63 and with the straight portion 17 of the tube 12 disposed in an oblique upward direction in axial alignment with the supporting pin 64. The ram 35 is then actuated to cause the movable die section 41 and the slidable die section 47 to be moved to their closed positions relative to each other and the stationary die section 40 and during the oblique downward movement of the slidable die section 47 of the pin 64 thereon enters the portion 17 of the tube 12 and cooperates with the pin 63 to support the precisely aligned walls of the tube 12 against distortion or collapse and to position the tube in a predetermined location within the die cavity 50. The charge of the molten metal is -then forced into the die cavity 50 to flow around the waveguide tube 12 and fill the die cavity, and after the metal has solidified the ram 35 is retracted, causing the movable and the slidable die sections 41 and 47, respectively, to be moved to their open positions after which the ejector pins 84 are actuated to eject the molded antenna horn from the mold. The surplus metal adhering to the antenna horn is then broken off or sheared from the body 12, leaving the completely formed streamlined antenna horn of a predetermined precise contour with the tube 12 molded therein providing a waveguide aperture of the desired size and configuration.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

An antenna horn for mounting on a high velocity object comprising a wave guide section having straight end portions and a bend intermediate the end portions and having a precisely uniform and smooth interior surface, a body around said wave guide having the form of a substantially right-angle pyramid and a complementing substantially obtuse pyramid, said right-angle pyramid having a triangular base, the hypotenuse side of the right-angle pyramid juxtaposed and forming a body around the wave guide section, said obtuse pyramid having a triangular base forming a continuation of the base of the right-angled pyramid, the obtuse side of the obtuse pyramid juxtaposed and forming a body around the wave guide section, one end of the wave guide section terminating at the vertexes of said pyramids, said other end portion of the wave guide section extending beyond the bases of said pyramids, and a circular ange extending from the molded body and surrounding the extended portion of the wave guide section below said bases for mating with a recess in the high vet locity object.

References Cited in the tile of this patent UNITED STATES PATENTS 

